Ubiquitous coverage which is the capability of a communication terminal device such as a mobile phone terminal that allows for wireless communications anywhere in the world is not practically used now, but is currently being developed.
These mobile systems include cellulars of GSM, GPRS, EDGE, WCDMA, DCS, and PCS. In the characteristics of these systems, there are increased demands for a multiband and a multimode with multiplex combinations in a wide range such as combinations between a constant envelope curve signal and a changed envelope curve signal, and between time division and code division. It should be noted that GSM is an abbreviation of Global System for Mobile Communication, GPRS is an abbreviation of General Packet Radio Service, EDGE is an abbreviation of Enhanced Data for GSM Evolution; Enhanced Data for GPRS, WCDMA is an abbreviation of Wideband Code Division Multiple Access, DCS is an abbreviation of Digital Cellular System, and PCS is an abbreviation of Personal Communication System.
Patent document 1 described below discloses a radio frequency transceiver incorporating a self-test function. The transceiver receives a signal at any one of a low RF band from 824 to 849 MHz and a high RF band from 869 to 894 MHz. On the other hand, the transceiver transmits a signal at a high RF band from 869 to 894 MHz. A transmitter of the transceiver supplies a specially-coded test signal at a low RF band from 824 to 849 MHz to a receiver of the transceiver. When the test signal is correctly received by the receiver, it can be determined that transmission and routes of receiving routes of receiving routes of receiving routes of receiving of the transceiver are correctly operated.
Patent document 2 described below discloses a technique by which the phases and amplitudes of an I-signal and a Q-signal that are orthogonally demodulated by a low IF (low intermediate-frequency) receiver that converts an RF received signal into a low IF signal are adjusted and unnecessary images are removed. In a calibration mode, an output signal of a transmission voltage controlled oscillator is supplied to a quadrature mixer for adjustment of the phases and amplitudes.
In addition, patent document 3, non-patent document 1, and non-patent document 2 described below disclose a demodulation device in which phase mismatch of an I-phase signal and a Q-phase signal that are demodulated by an orthogonal demodulation circuit is compensated by a phase mismatch compensation circuit, and amplitude mismatch of the I-phase signal and the Q-phase signal is compensated by an amplitude mismatch compensation circuit coupled to an output of the orthogonal demodulation circuit.    [Patent Document 1] Japanese patent laid-open No. Hei 10(1998)-93488    [Patent Document 2] Japanese patent laid-open No. Hei 11(1999)-251947    [Patent Document 3] Japanese patent laid-open No. 2004-40678    [Non-patent Document 1] Jeremie Chabloz et al, “A NOVEL I/Q MISMATCH COMPENSATION SCHEME FOR A LOW-IF RECEIVER FRONT-END”, Proceedings of the International Symposium on Circuits and Systems (ISCAS 2004), vol. 4, pp. 453-456, 2004 [Non-patent Document 2] Lawrence Der et al, “A 2-GHz CMOS Image-Reject Receiver With LMS Calibration”, IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 38, No. 2, FEBRUARY 2003, pp. 167-175